Memory devices are typically provided as internal, semiconductor, integrated circuits in computers or other electronic devices. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and non-volatile (e.g., flash) memory.
Flash memory devices typically use a one-transistor memory cell that may allow for high memory densities, high reliability, and low power consumption. Changes in threshold voltage of the cells, through programming of a charge storage structure, such as floating gates, trapping layers or other physical phenomena, may determine the data state of each cell.
Due to increasing data rates for flash memory input/output (I/O), meeting a setup/hold time is becoming more difficult for high speed flash memory. Presently, memory device setup/hold times can be trimmed during a manufacturing/testing operation. Once a nominal delay time is determined during the testing of the memory, this delay time can then be trimmed into all memory devices having those same circuits.
However, since each memory device can have slightly different characteristics due to doping levels or material differences, the nominal delay times may not provide the proper delay for all memory devices. There are resulting needs to provide improved delay time trimming for memory devices.